Penicillamine-induced proteinuria: risk factors

Drug-induced glomerular diseases

Drug-induced kidney diseases represent a wide range of diseases that are responsible for a significant proportion of all acute kidney injuries and chronic kidney diseases. In the present review, we focused on drug-induced glomerular diseases, more precisely podocytopathies - minimal change diseases (MCD), focal segmental glomerulosclerosis (FSGS) - and membranous nephropathies (MN), from a physiological and a pharmacological point of view. The glomerular filtration barrier is composed of podocytes that form foot processes tightly connected and directly in contact with the basal membrane and surrounding capillaries. The common clinical feature of these diseases is represented by the loss of the ability of the filtration barrier to retain large proteins, leading to massive proteinuria and nephrotic syndrome. Drugs such as non-steroidal anti-inflammatory drugs (NSAIDs), D-penicillamine, tiopronin, trace elements, bisphosphonate, and interferons have been historically associated with the occurrence of MCD, FSGS, and MN. In the last ten years, the development of new anti-cancer agents, including tyrosine kinase inhibitors and immune checkpoint inhibitors, and research into their renal adverse effects highlighted these issues and have improved our comprehension of these diseases.

Myasthenia gravis in a patient with pauciarticular juvenile chronic arthritis

There have been reported cases of children with histories of pauciarticular juvenile chronic arthritis (JCA) later developing myasthenia gravis (MG) as young adults. This is intriguing because it had been considered rare to diagnose a second autoimmune disease in a patient with pauciarticular JCA, unlike in those with adult-onset rheumatoid arthritis. We report a case of MG in a 20-year-old woman with a history of pauciarticular JCA. She presented with bilateral ptosis, weakness, and a history of dysphagia. The diagnosis was confirmed with positive serum acetylcholine receptor antibodies (2000 nm/L) and electromyography showing a decremental response to repetitive muscle stimulation. The patient's inflammatory arthritis was quiescent at diagnosis. The patient underwent a surgical thymectomy and was treated with pyridostigmine, intravenous immunoglobulin, and corticosteroids with a fluctuating clinical course. Previous cases have been reported of MG associated with this subtype of JCA, suggesting a connection in autoimmune pathology. The earlier recognition and management of MG in a patient with pauciarticular JCA presenting with weakness may improve the prognosis of this disease.

Penicillamine and nephrotic syndrome

BACKGROUND

Penicillamine (PA) treatment may be associated with a wide spectrum of adverse effects. There are many case reports and small series of PA-induced nephrotic syndrome (NS). In addition to our patient, in this study, we review all the cases of NS due to PA treatment in the English literature.

METHODS

A retrospective Medline search was done for the years 1963-2004 using the terms "penicillamine" and "proteinuria" or "penicillamine" and "nephrotic". Cases were also located through article references. Cases were included in our review only if they had enough clinical and laboratory data and if the NS was considered by the authors to be mainly or solely due to PA treatment. Diagnosis of the patient, dose and duration of PA treatment, maximal amount of proteinuria, kidney function, urine analysis, serological markers, clinical data, kidney biopsy results, treatment, and course of proteinuria were documented.

RESULTS

Sixty-three patients met our criteria. The female/male ratio was 40:23. Seventy-five percent of the patients had rheumatoid arthritis (RA). Mean age at diagnosis of NS was 44 (+/-S.D. 14) years. Mean dose of PA at diagnosis was 1.09 (+/-S.D. 0.413) g. Mean duration of PA treatment prior to proteinuria was 7.6 (+/-S.D. 3.90) months and mean duration of PA treatment until diagnosis of NS was 11.9 (+/-S.D. 18.8) months. Peak level of proteinuria was 10.79 (+/-S.D. 9.436) g. Some 33% of the patients developed mild to moderate renal failure at the time of diagnosis of NS, and one patient developed acute renal failure. Fifty-five percent of the patients had membranous glomerulonephritis and 27% had minimal change disease. Twelve patients were treated with corticosteroids (CS) at a dose ranging from 40 to 90 mg/day. In the overwhelming majority of patients, the proteinuria decreased significantly or disappeared within 7 months after stopping PA treatment. Patients treated with CS had a faster response. Five patients died, two of them from the CS-treated group, due to sepsis.

CONCLUSION

The mean duration of PA treatment prior to the development of NS is nearly 1 year (5 months after the development of proteinuria). The most common histopathological finding is membranous glomerulonephritis. Most patients will have a significant reduction in, or disappearance of, proteinuria within 7 months after stopping PA treatment. The decrease in proteinuria is faster with CS treatment.

Renal toxicity associated with disease-modifying antirheumatic drugs used for the treatment of rheumatoid arthritis

OBJECTIVE

To provide a review of the renal toxicity of disease-modifying antirheumatic drugs (DMARDs) currently used for the treatment of rheumatoid arthritis.

METHODS

Papers in American and European medical journals related to renal toxicity of DMARDs used for the treatment of rheumatoid arthritis were reviewed. Specific DMARDs reviewed were cyclosporine, gold, D-penicillamine, methotrexate, azathioprine, antimalarials, sulfasalazine, leflunomide, etanercept, infliximab, and DMARD combination therapy.

RESULTS

The renal toxicity of DMARDs varies widely. Cyclosporine, gold, and D-penicillamine all have a serious potential for renal side effects, particularly in the elderly or in patients with compromised renal function. Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) increases the potential for renal damage. In contrast, methotrexate, azathioprine, antimalarials, sulfasalazine, leflunomide, etanercept, and infliximab have relatively little renal toxicity.

CONCLUSIONS

The potential for renal toxicity should always be considered when determining which DMARD to use for RA therapy. DMARDs that combine efficacy with negligible renal adverse effects should be used for the treatment of patients susceptible to DMARD-associated renal damage.

Disease-modifying antirheumatic drugs. Potential effects in older patients

Disease-modifying antirheumatic drugs (DMARDs) are frequently used in rheumatoid arthritis. A number of physiological changes occur in the elderly which may modify the use of these medications. The most commonly used DMARDs are antimalarial drugs (particularly hydroxychloroquine), sulfasalazine and methotrexate. The principal mechanism of action of the antimalarials relates to the fact that they change intracellular pH, which downregulates numerous immune functions. Hydroxychloroquine is metabolised to 3 metabolites and has a very low clearance. It is moderately effective in dosages up to 6.4 mg/kg/day. While it is not the most effective of the DMARDs, it is the least toxic. Sulfasalazine is a prodrug which is enzymatically split in the bowel to form sulfapyridine (the principal active metabolite) and 5-aminosalicylic acid. The metabolism of sulfasalazine is complex and, to some extent, genetically determined. The mechanism of action of the drug is not well understood, but involves decreased production of cytokines and decreased proliferative response of lymphocytes. It may slow the rate of bony damage associated with rheumatoid arthritis. Nearly 50% of the patients who are prescribed sulfasalazine continue to receive the drug for up to 4 years. Sulfasalazine is not as well tolerated as hydroxychloroquine. Gastrointestinal toxicity, in particular, seems to be a problem in elderly patients taking this medication. Methotrexate is presently the most popular of the DMARDs for the treatment of rheumatoid arthritis. Methotrexate inhibits dihydrofolate reductase and adenosine release and has a secondary effect on cytokines and polymorphonuclear chemotaxis. It is highly metabolised within cells and remains there for prolonged periods. Up to 70% of patients who are prescribed methotrexate continue treatment for 5 years. Methotrexate treatment is associated with gastrointestinal, hepatic, cutaneous and, possibly, pulmonary adverse effects. The use of azathioprine, penicillamine and gold compounds is briefly reviewed in this article. Elderly patients have an increased incidence of rashes when using penicillamine, relative to young patients. There are no age-related differences in the efficacy and tolerability of azathioprine or gold therapy. The poor absorption and renal toxicity associated with cyclosporin, the new 'salvage' therapy in rheumatoid arthritis, make it generally unsuitable for use in the elderly, except under specialists' supervision.

Nephrotoxicity of xenobiotics

Nephrotoxicity can be grouped by the xenobiotics place of action, by the clinical presentation or by the generic toxic effect. The latter can be dose related, indirect, idiosyncratic or allergic. Nephrotoxicity of lithium, demeclocycline, aminoglycosides, cyclosporine, mercuric ion, nonsteroidal anti-inflammatory drugs, methoxyflurane, ethylene glycol, D-penicillamine and methicillin is reviewed in light of all these three viewpoints, but emphasis is on toxic mechanisms.